KR101540930B1 - Linear actuator and vacuum control device - Google Patents

Abstract

The linear actuator A includes a piston cylinder 31 having an opening 49 formed in the vacuum chamber 40 and heading toward the inside of the vacuum chamber 40 and reciprocating in a linear direction, And a driving unit 70 for reciprocating. The outer surface of the piston cylinder (31) is covered with a cylindrical member (32). The linear actuator A is formed in the opening 49 so that the cylindrical actuator 32 is slid while the inside of the vacuum chamber 40 and the outside of the vacuum chamber 40 are sealed (60). The cylindrical member 32 is configured to cover at least the sliding range including the second sliding range Lc in the piston cylinder 31. [ The outer surface of the cylindrical member 32 has a smaller amount of gas adsorbed per unit area than the outer surface of the piston cylinder 31.

Description

[0001] LINEAR ACTUATOR AND VACUUM CONTROL DEVICE [0002]

The present invention relates to a linear actuator and a vacuum control device used in a vacuum chamber in which plasma is generated.

For the fabrication of semiconductor devices, there is a process that uses a plasma, such as, for example, a plasma etch. In the plasma etching process, the vacuum pressure in the vacuum chamber is controlled, for example, while the etching gas is flowed by the vacuum control valve. The vacuum pressure is controlled by operating the conductance of the vacuum control valve. In a pendulum type vacuum control valve widely used for plasma etching, conductance is controlled by adjusting the valve opening degree by operating a pendulous valve element (Patent Document 1). However, the method of adjusting the pendulous valve element has a problem that it can not cope with the increase in the amount of the etching gas because the controllability to the proprietary area (low conductance region) is low.

On the other hand, a vacuum control valve of the poppet type corresponding to the increase in the amount of the etching gas has been conventionally used for controlling the vacuum pressure. A vacuum control valve of a poppet type is a system in which a valve element is formed in a piston (moving portion) of a linear actuator to adjust the conductance by controlling the distance (lift amount) between the valve element and the valve seat Document 2). Here, in the linear actuator employed in the vacuum control valve of the poppet type, a bellows is used to seal the sliding portion of the piston. Since this bellows is made of a metal having no plasma property, it is difficult to use a vacuum control valve of a poppet type in a vacuum chamber using plasma.

Patent Document 1: JP-A-2009-117444 Patent Document 2: JP-A-2010-276096 Patent Document 3: JP-A-2003-194257 Patent Document 4: JP-A-2000-130635 Patent Document 5: JP-A-03-260072

Thus, conventionally, there is no linear actuator that can be used in a vacuum chamber in which plasma is generated, and can linearly move the valve element or the like while maintaining a high degree of vacuum in the vacuum chamber.

An object of the present invention is to provide a linear actuator which can be used in a vacuum chamber in which plasma is generated.

Hereinafter, the effective means for solving the above-described problems will be described while showing effects and the like in accordance with necessity.

Means for Solving the Problem 1. A linear actuator for use in a vacuum chamber in which plasma is generated,

A moving unit capable of reciprocating in a linear direction from the outside to the inside of the vacuum chamber with an opening formed in the vacuum chamber;

A driving unit for reciprocating the moving unit,

A covering portion covering the moving portion,

And a sliding seal portion formed in the opening portion and sealing the space between the inside of the vacuum chamber and the outside of the vacuum chamber while sliding the cover portion,

And a covering portion which covers the covering portion and a region facing the inside of the vacuum chamber and the outside of the vacuum chamber in the moving portion when the moving portion reciprocates by the driving portion,

Wherein an outer surface of the covering portion is configured to have a smaller amount of gas adsorbed per unit area than an outer surface of the moving portion.

In the means 1, the covering portion covers a range from the inside of the vacuum chamber toward the outside of the vacuum chamber in the moving portion. Further, the outer surface of the covered portion has a smaller amount of gas adsorbed per unit area than the outer surface of the moving portion. Therefore, the gas is less likely to be adsorbed on the covering portion facing the outside of the vacuum chamber, and it is possible to suitably suppress the gas adsorbed on the covering portion from being carried into the vacuum chamber. That is, by suppressing the adsorption of gas to the moving part, it is possible to reliably seal the vacuum chamber.

In the case where the covering portion covers only a range facing the inside or outside of the vacuum chamber in the moving portion, the size of the covering portion becomes smaller as compared with the case where the covering portion covers the entire moving portion, .

Means 2. A linear actuator according to Item 1, wherein an attachment portion having a larger amount of gas adsorbed per unit area than an outer surface of the cover portion is formed at an end of the moving portion toward the inside of the vacuum chamber.

In the means 2, since the attachment portion is formed at the end portion of the movement portion, it is possible to attach the attachment portion to, for example, a valve or the like to the movement portion. Further, the attaching portion is formed at the end portion of the moving portion toward the vacuum chamber, and is always located inside the vacuum chamber. Therefore, there is no possibility that the attachment portion is directed to the outside of the vacuum chamber, and the gas is adsorbed from the outside of the vacuum chamber to the attachment portion. Therefore, it is possible to adopt an attachment portion having a larger adsorption amount than the outer surface of the cover portion. That is, it is not necessary to form the attaching portion from a member having high adhesiveness as the covering portion, and it is possible to suppress the material ratio and the processing cost.

Means 3. The linear actuator according to Item 1, wherein the covering portion has an insulating sintered body heated and hardened by heat treatment of a nonmetallic material having an insulating property.

In the means 3, since the covering portion has the sintered body in which the non-metallic material having the insulating property is heated and hardened by the heat treatment, high plasma resistance can be realized by the excellent insulating property of the sintered body. Further, the rigidity of the covering portion is improved, and the deterioration of the sealing structure can be effectively suppressed by the covering portion, and at the same time, it is possible to contribute to lowering the surface area (improvement in compactness) of the covering portion. That is, by using a sintered body having a smooth surface with a small unevenness as the covering portion, it is possible to suppress an increase in the surface area due to the unevenness.

Here, the present inventors have shown that many irregularities are generated on the surface of the moving portion even if, for example, an anodized film is formed on the surface of the moving portion made of aluminum and the anodized film is subjected to the sealing process. By employing a sintered body having a small unevenness as compared with the anodic oxidation coating, it is possible to remarkably reduce the adsorption amount of the covering portion.

Means 4. The linear actuator according to the means 3, wherein the sintered body is made of ceramics hardened by heating aluminum oxide.

In the means 4, since the sintered body is formed of ceramics in which aluminum oxide is heated and hardened, high structural strength and insulation can be realized by the material properties thereof.

Means 5. The linear actuator according to the means 1, wherein the moving portion is made of a metallic material.

In the means 5, since the moving portion is covered with the covering portion as described above, it is possible to adopt a metallic material having no plasma resistance as the moving portion.

Means (6) The linear actuator according to (5), wherein the moving part is made of aluminum.

In the means 6, since the movable portion is constituted by aluminum which is a general metal material, it is possible to facilitate the manufacture of the movable portion.

Means (7) The linear actuator according to (2), wherein the attaching portion is constituted by surface-oxidizing a metal material.

In the means 7, since the attaching portion is constituted by the surface-oxidized metal material, the insulating property of the attaching portion is ensured, and even if the attaching portion is exposed in the vacuum chamber, it is difficult to be affected by the plasma.

Means 8. The attachment portion is made of aluminum,

The surface oxidation treatment is an alumite treatment.

In the means 8, since the attaching portion is made of aluminum and an alumite treatment is adopted as the surface oxidation treatment, the influence from the plasma can be appropriately suppressed even if the attaching portion is exposed inside the vacuum chamber.

Means 9. A guide rod connected to the moving portion and extending along the center of the axis of the moving portion,

And a guide portion for guiding the guide rod in a moving direction of the moving portion.

In the means 9, since the guide portion guides the guide rod, it is possible for the moving portion to move stably. Therefore, it is not necessary to make a guide for guiding the moving part to the sliding bag part to which the moving part is slid, and it is possible to prevent the sealing ability of the sliding bag part from deteriorating by forming the guide.

Means 10. A linear actuator according to clause 2, wherein said linear actuator is attached to said attachment portion and has an actuating portion that operates within said vacuum chamber.

In the means 10, since the operating portion is made in the mounting portion, it is possible to operate the operating portion by operating the operating portion in the vacuum chamber.

11. The linear actuator according to claim 10, further comprising an insertion passage for inserting a control line for controlling the operation of the actuating portion from the outside of the vacuum chamber to the inside of the actuating portion.

In the means 11, it is possible to connect a control line for controlling the operating portion to the operation portion by inserting the control line into the insertion passage.

Means 12. The covering portion is made of a pair of elastic sealing portions which are mutually spaced apart in the moving direction of the moving portion so as to have a predetermined gap with respect to the outer surface of the moving portion,

Wherein the pair of elastic sealing parts are provided on the outer surface of the moving part in such a manner that the linear actuator

In the means 12, a pair of elastic sealing members elastically contacted with the moving portion are formed, and a gap between the covering portion and the moving portion is sealed with both elastic sealing members. Thereby, even when the thermal expansion amounts of the covering portion and the moving portion are different when the environmental temperature is changed, the difference in the thermal expansion amount can be absorbed by the elastic sealing member. Therefore, the degree of freedom in selecting the material of the covering portion and the moving portion is increased, and for example, a metal material (aluminum or the like) excellent in strength and toughness is selected as the material of the moving portion while a sintered body of aluminum oxide It becomes possible to select.

13. The sliding bag according to claim 12,

A sliding surface on which said cover portion is slidable,

A first sliding bag member and a second sliding bag member spaced apart from each other in the moving direction of the moving unit and disposed on the sliding surface and defining a vacuum sliding chamber between the sliding surface and the covering unit;

And a vacuum suction passage communicated with the vacuum sliding chamber,

The first sliding sealing member abuts against the outer surface of the covering portion to seal between the inside of the vacuum chamber and the vacuum sliding chamber,

The second sliding sealing member is in contact with the outer surface of the covering portion to seal between the vacuum sliding chamber and the outside of the vacuum chamber and the outside of the vacuum chamber,

And the inside of the vacuum oscillating chamber is configured to be vacuum-sucked with the vacuum suction passage.

In the actuator of the means 13, since the vacuum sliding chamber capable of vacuum suction is formed so as to face the sliding surface on which the cover portion is slid, the portion facing the vacuum sliding chamber in the covering portion can be vacuum-sucked. Therefore, it is possible to further suppress the adsorption of the gas to the covering portion, and it is possible to reliably seal the inside of the vacuum chamber. Further, since the dust attached to the covering portion can be removed by vacuum suction in the vacuum sliding chamber, it is possible to appropriately suppress the foreign matter adsorbed on the covering portion to enter the inside of the vacuum chamber. Further, by forming the first sliding bag member and the second sliding bag member in the moving direction of the moving part, the vacuum sliding chamber is formed as a region extending along the moving direction of the moving part. Therefore, it is possible to secure the region of the vacuum-suctionable covering portion in the moving direction of the moving portion in the vacuum sliding chamber, and the range of vacuum suction in the moving portion can be increased.

Here, in the case where the moving portion is reciprocated so that the portion facing the vacuum chamber and the outside of the vacuum chamber (the outside of the vacuum chamber) is generated in the covering portion, the portion of the covering portion facing the outside of the vacuum sliding chamber But there is a possibility that the gas adsorbs. However, since the portion is vacuum-sucked when it passes through the vacuum sliding chamber, it is possible to suppress the gas adsorbed on the covering portion from being conveyed to the inside of the vacuum chamber.

Means 14. The first sliding bag member comprises:

An elastic body having two ribs branched from each other and the branched ribs abutting on the sliding surface and the covering portion,

And a biasing member that urges the branched lip in a direction of mutually separating the linear actuators.

In the means 14, there is formed a biasing member which biases the ribs in the direction in which they are separated from each other, so that even when the vacuum sliding chamber is evacuated by vacuum suction, the lip is surely abutted against the abrading surface And it is possible to realize a high sealing performance.

Means 15. Means 13 A control unit for controlling the linear actuator based on the control unit,

Wherein the control unit controls the driving unit so that a range of the movable unit toward the inside of the vacuum chamber during the reciprocating movement of the moving unit by the driving unit can be moved within the range of the vacuum chamber and the vacuum sliding chamber A vacuum control device having a conductance operation mode.

In the means 15, the control unit performs a conductance operation mode in which the driving unit is controlled so that the range of the moving unit facing the inside of the vacuum chamber can be moved within the range of the vacuum chamber and the vacuum sliding chamber. As a result, it is possible to prevent the gas from being carried into the vacuum chamber without the range exposed to the outside of the vacuum sliding chamber in the covering portion being directed to the inside of the vacuum chamber during the conductance operation mode. As a result, in the conductance operation mode, it is possible to maintain the inside of the vacuum chamber at a higher degree of vacuum.

16. The apparatus according to claim 1, wherein, before the start of the conductance operation mode, the control unit sets a range of the moving part toward the outside of the vacuum swing chamber from the vacuum chamber side to the vacuum And a release mode in which the vacuum suction passage is provided in a state of being moved in the sliding chamber to vacuum suction the inside of the vacuum suction chamber only for a predetermined time.

In the means 16, before the start of the conductance operation mode, the control unit sets the departure mode for evacuating the movable chamber toward the outside of the vacuum chamber from the side of the vacuum chamber toward the outside of the vacuum chamber, . Thus, the conductance operation mode is started in a state in which the cover body is removed, so that it is possible to suppress the transportation of the gas to the vacuum chamber.

17. The apparatus of claim 16,

A cylinder disposed outside the vacuum chamber and through which the working fluid flows,

A piston which is arranged to define a working chamber inside the cylinder and moves in the cylinder by the pressure of the working fluid supplied into the working chamber;

(Urging portion) for urging the piston toward the vacuum chamber,

And the moving unit is connected to the piston.

In the means 17, since the piston generates a load in response to the pressure of the working fluid, it is suitable for an explosion-proof environment and can generate a small and large driving force. Thus, it is possible to realize a linear actuator suitable for a semiconductor manufacturing apparatus.

Furthermore, as another means for realizing the control function of the vacuum control device, the computer program can be embodied as a computer program having a program for realizing the control function of the conductance operation mode in the control device.

It is also possible to embody, for example, a vacuum control method or a program medium embodying the method.

1 is a cross-sectional view showing a vacuum control valve in a non-operation state (valve full closing) to which a linear actuator according to the first embodiment is applied;
2 is an enlarged sectional view showing a swinging portion of a vacuum control valve;
3 is a cross-sectional view showing a vacuum control valve when the valve is fully opened;
4 is a bottom view of the vacuum control valve in a non-operating state (valve closed state) as seen from a section of the valve element.
5 is a cross-sectional view showing an operating state at the time of controlling the vacuum pressure of the vacuum control valve.
6 is an enlarged cross-sectional view of the sealing member.
7 is a flowchart showing an example of the operation of the vacuum control valve.
8 is a sectional view showing a linear actuator in operation according to the second embodiment;
9 is a perspective view showing a cancer.
10 is a cross-sectional view showing a linear actuator in operation according to a modification example;

Hereinafter, a first embodiment will be described with reference to the drawings. The first embodiment is embodied by a vacuum control valve 10 in which a valve element 33 is provided in a linear actuator A and its vacuum control device. The vacuum control valve 10 is used in a semiconductor manufacturing apparatus that performs an etching process using a plasma.

(Basic configuration of vacuum control valve)

1, the semiconductor manufacturing apparatus includes a vacuum chamber 40 (vacuum chamber) for vacuum processing a work (not shown in the figure) to be processed such as a substrate, and a plasma is generated inside the vacuum chamber 40 . The vacuum chamber (40) is provided with an opening (49) communicating the inside and the outside of the vacuum chamber (40). In the opening 49, the vacuum control valve 10 is formed. The vacuum control valve 10 is basically composed of a linear actuator A and a valve element 33 linearly moved by the linear actuator A in the vacuum chamber 40. Further, in the following description, the inside of the vacuum chamber 40 refers to an area inside the inner wall surface of the vacuum chamber 40. More specifically, the inside of the vacuum chamber 40 refers to the area inside the vacuum chamber 40, rather than the sealing member 68 described later. The outside of the vacuum chamber 40 refers to an area outside the inner wall surface of the vacuum chamber 40. More specifically, the outside of the vacuum chamber 40 refers to the area outside the vacuum chamber 40 rather than the sealing member 68.

The linear actuator A includes a driving unit 70 positioned outside the vacuum chamber 40 and an actuating unit 30 for moving the driving unit 70 in an axial direction do. The linear actuator A has a sliding portion (sliding piece portion) 60 for sealing the opening portion 49 while allowing the operation portion 30 to slide, and maintaining the degree of vacuum inside the vacuum chamber 40 Respectively. The sliding portion 60 is formed between the vacuum chamber 40 and the driving portion 70 and is attached to the opening portion 49.

A connecting communication port 45 (see FIG. 3) is formed in the wall portion (lower side in FIG. 1) opposite to the wall portion in which the opening 49 is formed in the vacuum chamber 40. The connection port 45 constitutes a connection port 44, and a vacuum pump is connected to the connection port 44. The connecting communication port 45 has a rectangular opening shape elongated in one direction (left and right direction in Fig. 1). The inner wall surface (the upper surface of the lower wall portion in Fig. 1) of the vacuum chamber 40 in which the connecting communication port 45 is opened constitutes the valve seat 43 in which the valve element 33 is seated. Further, the surface roughness of the valve seat 43 is configured to be lower than the other portions of the vacuum chamber 40 (the degree of flatness is high).

The valve element 33 has a rectangular shape in which the surface on the side of the connecting communication port 45 (hereinafter referred to as a lower surface) is larger than the opening area of the connecting communication port 45. When the valve element 33 is seated on the valve seat 43, the connection communication port 45 is closed. As shown in Fig. 4, an O-ring 35 is mounted on the bottom surface of the valve element 33 so as to protrude from the connection communicating port 45 side (lower side).

The operating portion 30 has a columnar piston rod (moving portion) 31 to which the valve element 33 is attached. The operating portion 30 is also provided with a cylindrical cylindrical member (covering portion) 32 that covers the outer peripheral surface (outer surface) of the piston rod 31. The operating portion 30 is directed to the inside of the vacuum chamber 40 with the opening 49 (specifically, a through hole formed in the sliding portion 60). The piston rod 31 has a cylindrical shape elongated in the moving direction of the piston rod 31. 2, an annular annular protruding in the outer diameter direction of the piston rod 31 is formed in the outer end portion (upper end in Fig. 2) of the vacuum chamber 40 of the piston rod 31, , A ring-shaped positioning projection portion 53 is formed. One end of the cylindrical member 32 abuts against the positioning projection 53, and the cylindrical member 32 is positioned.

An attachment portion 31c is formed at an end portion (lower end portion in FIG. 1) of the piston rod 31 which faces toward the inside of the vacuum chamber 40. As shown in FIG. The central portion of the attachment portion 31c protrudes in the moving direction of the piston rod 31 (downward in Fig. 1). In the first embodiment, the piston rod 31 and the attachment portion 31c are integrally formed of aluminum, which is a metallic material. The valve element 33 is fixed to the piston rod 31 by screwing the valve element 33 to the mounting portion 31c with a plurality of bolts 33a. Furthermore, the attachment portion 31a may be formed of a member other than the piston rod 31. [

On the other hand, in the interior of the piston rod 31, a cylindrical space is formed in the end surface opposite to the attachment portion 31c. This cylindrical space constitutes a blocking load generating chamber 39 for generating a force for urging the piston rod 31 and the valve element 33 to the valve seat 43 side (see Fig. 2). Further, the specific configuration of the cylindrical member 32 will be described later.

The driving unit 70 includes a cylindrical cylinder tube (cylinder) 71 formed outside the vacuum chamber 40. The driving unit 70 also includes a piston 51 formed inside the cylinder tube 71 and movable in the axial center direction (vertical direction in Fig. 1). The driving unit 70 further includes a biasing spring 75 for biasing the piston 51 toward the vacuum chamber 40 (the lower side in FIG. 1).

The cylinder tube 71 is formed on the surface of the sliding portion 60 facing the outside of the vacuum chamber 40 (the upper surface in FIG. 1). The cylinder tube (71) surrounds the opening (49) from the outside of the vacuum chamber (40). The opening of the cylinder tube 71 on the side opposite to the vacuum chamber 40 is closed by the head cover 81.

The piston 51 extends in the radial direction from the end portion of the piston rod 31 opposite to the valve element 33 toward the inner peripheral surface 73 of the cylinder tube 71, (Upward in Fig. 1) in a direction away from the vacuum chamber 40 in the vicinity of the vacuum chamber 73. That is, the piston 51 is integrally formed with the piston rod 31 and has an annular shape opened to the side opposite to the vacuum chamber 40 (upper side in FIG. 1).

The piston 51 is moved to the valve opening operation chamber 36 by the cylinder tube 71, the piston 51, the sliding portion 60 and the cylindrical member 32 in the state where the piston 51 is formed inside the cylinder tube 71 Operating room, see Fig. 3) is defined. The piston 51 is provided with an annular piston plug 51a. The piston plug 51a is formed on an outer circumferential surface of the piston 51 facing the inner surface 73 of the cylinder tube 71 and protrudes in the outer diameter direction of the piston 51. [ The piston plug 51a elastically abuts on the inner circumferential surface 73 of the cylinder tube 71 to seal between the outer circumferential surface of the piston 51 and the inner circumferential surface 73 of the cylinder tube 71 . The valve opening operation chamber 36 is sealed by the piston seal 51a and a V-packing 67 described later.

The valve opening operation chamber 36 is formed as a donut-shaped (annular) closed space whose volume changes. The valve opening operation chamber 36 is provided with an air flow passage 21 for opening a valve formed in the cylinder tube 71 and a connecting flow passage 22 formed in the sliding portion 60, It is in communication with the source. The working air (working fluid) is supplied to the valve opening operation chamber 36 by opening the valve opening air passage 21 and the connection passage 22 from the air supply source. That is, by supplying the operating air from the air supply source to the valve opening operation chamber 36, the volume of the valve opening operation chamber 36 is increased. Thus, the piston 51 is moved in a direction away from the vacuum chamber 40 (upper side in Fig. 1). That is, the pressure of the working air supplied to the valve opening operation chamber 36 acts in the direction of opening the valve element 33. [

The biasing spring 75 is disposed in the cylinder tube 71 in a state of being engaged with the head cover 81 and the piston 51. The bias spring (75) abuts against the head cover (81) and the piston (51). The biasing spring 75 biases the piston 51 toward the vacuum chamber 40 (the lower side in Fig. 1) by the elastic force.

The head cover 81 is provided with a cylindrical portion 82 and a sliding convex portion 83 extending in the moving direction of the operating portion 30 in the cylinder tube 71. The cylindrical portion 82 has a cylindrical shape in which the axial center coincides with the operating portion 30. The sliding convex portion 83 is connected to the end portion (the lower end in FIG. 1) of the cylindrical portion 82 on the side of the vacuum chamber 40. The sliding convex portion 83 has a cylindrical shape in which the shaft portion and the cylindrical portion 82 coincide with each other. The outer diameter of the sliding convex portion (83) is smaller than the outer diameter of the cylindrical portion (82). A stroke restricting face 84 (stroke restricting face) opposite to the vacuum chamber 40 is formed at a connecting portion between the sliding convex portion 83 and the cylinder portion 82. The head cover 81 is provided with a valve closing air passage 81a communicating with the blocking load generating chamber 39 through the inside of the cylinder portion 82 and the sliding convex portion 83 Respectively. The valve closing air flow path 81a is connected to an air supply source (not shown), and a bell closing air flow path 81a is provided from the air supply source so that operating air (working fluid) .

3, the stroke restricting surface 84 is formed at a position where the stroke restricting surface 84 abuts against the piston 51, and the stroke restricting surface 84 abuts on the piston 51, Is limited. That is, the movement of the piston 51 in the direction in which the lift amount La increases (upward in FIG. 1, hereinafter referred to as the opening direction) is restricted by the stroke limiting surface 84. On the other hand, the movement of the piston 51 in the direction in which the lift amount La decreases (downward in Fig. 1, hereinafter referred to as the closing direction) is determined by the contact between the valve element 33 and the valve seat 43 . Further, a portion of the piston 51 abutting the stroke restricting surface 84 is referred to as a stroke restricting end portion 56. [

The sliding convex portion 83 has an outer shape that substantially matches the blocking load generating chamber 39. When the piston 51 moves in the opening direction, the sliding protrusion 83 is received in the blocking load generating chamber 39 (see FIG. 3). On the outer peripheral surface of the sliding convex portion 83, a packing 39b having a V-shaped cross section is annularly mounted. The packing 39b abuts against the inner circumferential surface of the blocking load generation chamber 39 to seal the inner peripheral surface of the sliding convex portion 83 and the blocking load generation chamber 39 (see FIG. 2).

Here, when working air is supplied to the breaking load generating chamber 39, the volume of the breaking load generating chamber 39 increases. As a result, the piston rod 31 is biased toward the connection port 44 (the lower side in Fig. 1). That is, the pressure of the working air that has been supplied to the blocking load generation chamber 39 acts on the direction in which the valve element 33 is closed. For this reason, it is possible to compensate the force by which the biasing spring 75 biases the piston 51 in the closing direction by the breaking load generating chamber 39. Therefore, the urging force necessary for the biasing spring 75 can be reduced. As a result, it is possible to reduce the load (load at the time of interruption) when the biasing spring 75 is set at the time of manufacturing, and it is possible to improve the productivity of the vacuum control valve 10. Further, on the inner peripheral surface of the sliding convex portion 83, a second packing 39a is annularly formed on the inner side of the packing 39b. The second packing 39a is brought into contact with the guide rod 38 to be described later so as to seal the space between the sliding convex portion 83 and the guide rod 38 (see Fig. 2).

On the inside of the sliding convex portion 83, a linear bearing (guide portion) 85 is provided. In the first embodiment, as the linear bearing portion 85, a linear bush is employed. A guide rod 38 to which the piston rod 31 is connected is slidably inserted into the linear bearing portion 85. The guide rod 38 has a cylindrical shape extending in the moving direction of the piston rod 31 along the axis of the piston rod 31. The linear bearing portion 85 guides the guide rod 38 to guide the relative movement of the piston rod 31 (the operating portion 30), the driving portion 70 and the sliding portion 60 in the radial direction A smooth reciprocating movement of the piston rod 31 is realized while defining the positional relationship.

In the head cover 81, a valve element position sensor 90 is provided. The valve element position sensor 90 includes a probe 92 extending in the moving direction of the piston rod 31 in the cylinder tube 71. The valve element position sensor 90 is provided with an insertion tube 94 into which one end (lower end in FIG. 1) of the probe 92 is inserted. The other end (the upper end in Fig. 1) of the probe 92 is fixed to the probe mounting portion 91 for closing the opening of the barrel 82. [ The insertion tube 94 is fixed in the guide rod 38 with an insertion tube mounting member 93 provided inside the guide rod 38. The valve element position sensor 90 is adapted to generate an electrical signal corresponding to the insertion amount of the probe 92 into the insertion tube 94. That is, it is possible to grasp the lift amount La of the valve element 33 by measuring the amount of movement of the piston rod 31 in the valve element position sensor 90. As a specific valve element position sensor 90, a linear pulse coder (registered trademark) can be exemplified.

1, the vacuum control valve 10 is provided with a shutoff function (the lift amount La is 0) for shutting off the connection port 44 and the inside of the vacuum chamber 40 at the time of non-operation, As shown in Fig. 5, a conductance adjusting function (fluctuation of the lift amount La) for operating the conductance of the vacuum control valve 10 at the time of operation is provided. Conduction refers to ease of flow of gas in the vacuum chamber 40 through the vacuum control valve 10. That is, the conductance adjustment function is realized by operating the lift amount (the movement amount of the moving part) La, which is the distance between the valve element 33 and the valve seat 43, as the valve opening degree.

On the other hand, the blocking function is performed by bringing the valve element 33 into contact with the valve seat 43 and closing the connection communication port 45 in the vacuum chamber 40 as shown in Fig. 1 (Fully closed state). The sealing at the time of blockage is realized by pressing the O-ring 35 of the valve element 33 against the valve seat 43 to be crushed. 3, the vacuum control valve 10 is moved to the valve element 33 until the valve element 33 comes close to the sliding portion 60 (the lift amount La is the maximum) So that it is possible to move it linearly.

(Mechanism of Vacuum Control Valve Adsorption and Bag Structure)

Hereinafter, the mechanism of suction and conveyance of the working air (working fluid) which causes the degree of vacuum in the vacuum chamber 40 to decrease will be described below. The working air is a gas composed mainly of nitrogen and oxygen. 3), the gas molecules of the working air flow into the operating portion 30 (see FIG. 3), and when the operating portion 30 faces the inside of the valve opening operation chamber 36 ) (For example, physical adsorption or chemisorption). 1, when the portion of the operating portion 30 facing the valve opening operation chamber 36 moves into the vacuum chamber 40, the gas molecules adsorbed to the operating portion 30 (Released) into the interior of the vacuum chamber 40.

That is, in the operating section 30, the range in which any of the inside of the vacuum chamber 40 and the valve opening operation chamber 36 faces is defined as the first sliding range (the inside of the vacuum chamber and the vacuum (The range in which any one of the outside of the chamber and the outside of the vacuum sliding chamber faces) Lb (see Figs. 1 and 3). That is, the first sliding range Lb is set to be the same as the first valve opening range Lb when the lift amount La is manipulated so that the valve element 33 is in the fully closed state and the deployed state (30) exposed to both the vacuum chamber (36) and the vacuum chamber (40).

As described above, in the case where the operating portion 30 is reciprocated so that the valve element 33 is in the deployed state and the fully closed state when the cylindrical member 32 is not equipped, the first sliding range Lb, The adsorption of the working air in the valve opening operation chamber 36 and the discharge of the working air in the vacuum chamber 40 are caused. When the operation of the working air from the valve opening operation chamber 36 to the vacuum chamber 40 occurs, the degree of vacuum in the vacuum chamber 40 decreases (pressure rises).

In view of the above-described problem, the present inventors have found that by covering the piston rod 31 with the cylindrical member 32 having low adsorptivity, it is possible to suppress the movement of the working air from the valve opening operation chamber 36 to the vacuum chamber 40 Technology. In the first embodiment, the cylindrical member 32 covers substantially the entire outer surface of the piston rod 31 in the longitudinal direction (the vertical direction in FIG. 1). That is, the dimension in the axial direction of the cylindrical member 32 is the same as the dimension from the positioning projection 53 in the piston rod 31 to the end portion (the lower end in FIG. 1) opposite to the positioning projection portion 53 Respectively. The cylindrical member 32 is extruded from the attachment portion 31c toward the piston rod 31 before the valve element 33 is attached. In this state, the cylindrical member 32 is mounted on the piston rod 31 by fixing the valve element 33 to the attachment portion 31c. At this time, both ends of the cylindrical member 32 in the longitudinal direction are sandwiched by the positioning protrusion 53 and the valve element 33. Thereby, the cylindrical member 32 is fixed to the piston rod 31 without being shaken in the axial direction.

The cylindrical member 32 is composed of a sintered body (ceramics) formed by heating and solidifying aluminum oxide (alumina). The irregularities on the surface of the cylindrical member 32 are suppressed by the high compactness of the sintered body and the low adsorptivity of the gas molecules of the cylindrical member 32 is realized. As a result, the cylindrical member 32 has a smaller amount of gas adsorbed per unit area than the outer surface of the piston rod 31.

Therefore, the inventors of the present invention confirmed that the cylindrical member 32 formed of the sintered body has a lower adsorption amount of working air, compared to, for example, a case where the anodic oxidation coating formed on the piston rod made of aluminum is subjected to the sealing treatment . Further, the cylindrical member 32 has plasma resistance due to the high insulating property of the sintered body. Further, because the attachment portion 31c for attaching the valve element 33 to the piston rod 31 is always located inside the vacuum chamber 40, the operation air is directed toward the outside of the vacuum chamber 40 There is no fear of adsorption. Therefore, the attaching portion 31c is not required to have low adsorbability such as that of the cylindrical member 32, and the adsorbing property of the outer surface of the attaching portion 31c is higher than that of the cylindrical member 32. [

Here, as the sintered body of the cylindrical member 32, it is preferable to use ceramics of dense alumina having a relative density of 95% or more. However, if the relative density of the sintered body is 90% or more, there is a certain effect, and a sintered body having a relative density higher than that of, for example, 96%, 97%, or 98% may be employed corresponding to the required degree of vacuum. Furthermore, it is also possible to suppress the carrying amount of the working air to a low limit by using ceramics of 99% or more of high purity dense alumina.

Furthermore, if the surface of the ceramics of dense alumina is mirror-finished with an average surface roughness (0.2 Ra) of 0.2 or more, the adsorption of the cylindrical member 32 can be further reduced. Further, a high sealing property is ensured, and it is possible to reduce the friction between the cylindrical member 32 and the V-packing 67 or the sealing member 68, which will be described later. The reduction of the friction can contribute to the low hysteresis characteristic of the vacuum control valve 10. [ The average surface roughness is appropriately set to a value of 0.1, 0.3, 0.4 or 0.5 corresponding to the specification of the vacuum control valve 10. [

As shown in Fig. 2, the cylindrical member 32 is formed on the outer surface of the piston rod 31 by making a clearance as much as the clearance Cr. The clearance (Cr) is sealed by O rings (31a, 31b) as a pair of ring-shaped elastic sealing parts to the piston rod (31). The O-rings 31a and 31b are elastic members which are disposed apart from each other in the moving direction of the piston rod 31. [ Each of the O-rings 31a and 31b is resiliently abutted against the inner circumferential surface of the cylindrical member 32, so that the clearance Cr is sealed.

Thus, even when the thermal expansion amounts of the cylindrical member 32 and the piston rod 31 are different, the O-rings 31a and 31b are elastically deformed to absorb a different amount of the thermal expansion amount. As a result, it is possible to increase the degree of freedom in selecting the material of the cylindrical member 32 and the piston rod 31. [ For example, a metal material (for example, aluminum) having excellent strength and toughness is employed as the material of the piston rod 31, and a sintered body of aluminum oxide having excellent insulating properties is selected as the material of the cylindrical member 32 .

As described above, by adopting the piston rod 31 made of a metal material excellent in strength and toughness and the double-structured operating portion 30 made of the low-adsorption cylindrical member 32, the vacuum chamber 40 using plasma is used, The vacuum control valve 10 (linear actuator A) of the poppet type usable in the vacuum pump is realized. As a result, in the vacuum chamber 40 for generating a plasma, it becomes possible to realize an increase in the amount of etching gas (minute flow).

Fig. 5 is a cross-sectional view showing an operating state in controlling the vacuum pressure of the vacuum control valve 10 (when manipulating the conductance). There is a case where the cylindrical member 32 is adsorbed with a small amount of operating air even if the above-mentioned low-adsorptive cylindrical member 32 is used. Therefore, there is a possibility that a very small amount of leakage (lowering of the degree of vacuum) in the vacuum chamber 40 during the operation of the conductance occurs and the high vacuum can not be maintained. Thus, the vacuum control valve 10 is provided with a vacuum suction function in the sliding portion 60 so as to suppress the leakage of this minute amount.

As shown in Fig. 2, the sliding portion 60 includes a sliding portion main body 60a and a sliding contact surface 60b. The sliding portion main body 60a is provided in the vacuum chamber 40 like the opening 49 is closed. The sliding surface 60b is formed in the sliding portion main body 60a by making a through hole opening in the moving direction of the piston rod 31. [ And the cylindrical member 32 is slid with respect to the sliding surface 60b. A V packing (second sliding sealing member) 67 and a sealing member (first sliding sealing member) 68 disposed apart from each other in the moving direction of the piston rod 31 are formed on the sliding surface 60b Is installed. The V packing 67 and the sealing member 68 define a vacuum sliding chamber S between the sliding portion 60b and the cylindrical member 32. [

The sliding portion main body 60a includes a vacuum suction region forming member 62 positioned between the V packing 67 and the sealing member 68 and a vacuum suction region forming member 62 disposed in the vacuum chamber 40. [ (A lower side in Fig. 1). The vacuum suction region forming member 62 is an aluminum member formed in a donut shape so as to surround the cylindrical member 32. The vacuum suction region forming member 62 is formed with an annular concave portion 62a defining a vacuum sliding passage 25 having a small clearance with the cylindrical member 32.

The vacuum sliding passage 25 is connected to an annular connecting passage 24 defined between the vacuum suction region forming member 62 and the sliding portion main body 60a and extending in the radial direction of the sliding portion 60 have. The connection passage 24 is connected to the vacuum suction passage 23. The vacuum suction passage 23 extends in the radial direction inside the sliding portion main body 60a and opens at the outer side of the sliding portion main body 60a. The vacuum suction passage 23 is connected to the vacuum pump. That is, the vacuum sliding chamber S communicates with the vacuum pump through the vacuum sliding passage 25, the connecting passage 24, and the vacuum suction passage 23.

As shown in Fig. 2, the V packing 67 is formed in a V-shaped cross section which is mutually separated from the inside of the vacuum chamber 40 toward the outside (from the lower side to the upper side in Fig. 1). The V packing 67 is in contact with the entire circumference of the outer surface of the cylindrical member 32 and is connected to the vacuum swing chamber S and the valve opening operation chamber 36 And the outside of the chamber S). The V packing 67 is biased in the expanding direction by the pressure in accordance with the operating air of the valve opening operation chamber 36, so that the sealing ability is increased.

6 is an enlarged cross-sectional view showing the sealing member 68. The sealing member 68 is in contact with the entire circumference of the outer surface of the cylindrical member 32 and is disposed inside the vacuum chamber 40, And the gap between the sliding chamber (S) is sealed. The seal member 68 is basically composed of a rotovary seal (registered trademark) 68f and a metal spring (seal member) 68e. The rotovari yarn (elastic body) 68f has a bifurcated lip (lobe) 68a. The branch lip 68a abuts on the sliding surface 60b and the cylindrical member 32, respectively. When the pressure of the vacuum sliding chamber S increases, the rotovarie chamber 68f expands so that the seal lips 68a are separated from each other, thereby increasing the sealing ability.

A heel flange 68c is formed in the rotatable chamber 68f so that the heel flange 68c is formed on the inner surface 63a of the support member 63 and the inner surface 63a of the vacuum suction region forming member 62 (62b). The metal spring 68e is provided between the seal lips 68a in a resiliently deformed form and is urged in a direction in which the seal lips 68a are separated from each other. Therefore, even when the sealing member 68 is in a state in which the vacuum sliding chamber S is vacuum-sucked, the sealing ability of the sealing member 68 is maintained by the elastic force of the metal spring 68e. The heel flange 68c seals the space between the vacuum chamber 40 and the vacuum suction passage 23 together with the O ring 69 provided in the vacuum suction region forming member 62 ).

According to the above-described sealing structure by the sliding portion 60, vacuum suction is performed in the vacuum sliding chamber S, and as described below, it is possible to suppress the adsorption of working air to the cylindrical member 32 . As described above, the cylindrical member 32 is configured to have a low adsorption property. When the cylindrical member 32 is directed to the valve opening operation chamber 36, a small amount of operating air may be adsorbed to the cylindrical member 32 . The small working air adsorbed by the cylindrical member 32 is released from the cylindrical member 32 in the vacuum sliding chamber S.

Since the vacuum sliding chamber S is vacuum-sucked by the vacuum pump, the working air discharged into the vacuum sliding chamber S flows through the vacuum sliding passage 25, the connecting passage 24, (23), and is discharged to the outside of the vacuum chamber (40). Thus, accumulation of the working air in the vacuum sliding chamber S is suppressed. In other words, it is possible to suitably suppress that the working air discharged into the vacuum sliding chamber S is sucked back to the cylindrical member 32 and conveyed to the vacuum chamber 40. This makes it possible to suppress the decrease in the degree of vacuum in the vacuum chamber 40 and to maintain the vacuum chamber 40 in a high vacuum state (for example, high vacuum).

In addition, since the dust attached to the cylindrical member 32 can be removed by vacuum suction in the vacuum sliding chamber S, it is also possible to suppress entry of foreign matter into the vacuum chamber 40.

It is also possible to arrange the flow path on the sliding surface 60b of the sliding portion 60 such that an inspection flow path to a leak inspection port (not shown) Is a suction flow path for preventing leakage of toxic gas from the outside to the outside. This inspection flow path is used for leakage detection using helium gas. That is, in the set-up operation, helium gas is released near the leakage inspection port, and the leakage to the sliding portion is detected as the arrival of the helium gas into the vacuum chamber 40. On the other hand, the suction passage is a port for sucking toxic gas.

Therefore, this configuration is essentially different from the above-described configuration and use, and the shape of the vacuum sliding chamber S also differs from the above-described respective structures. In addition, the vacuum sliding chamber S forms a tubular space formed over a predetermined length in the operating direction of the piston rod 31 (between the V packing 67 and the sealing member 68) . In the tubular space, a vacuum sliding passage 25 is also formed in a central portion in the longitudinal direction. Such a tubular space has a shape that does not match any of the above-described configurations, and thus contradicts the technical knowledge of those skilled in the art at the time of filing.

7 is a flowchart showing an example of the operation of the vacuum control valve 10. As shown in Fig. In step S10, a first vacuum suction step is performed. The first vacuum suction step is a step of controlling the compression rate of the O-ring 35 (see Figs. 1 and 3) provided in the valve element 33 and discharging it at a low speed in the initial stage of vacuum suction Process). The slow evacuation process is proposed by a person skilled in the art and is carried out to prevent particles in the vacuum chamber 40 from being lifted up (Japanese Patent Application Laid-Open No. 2000-163137).

In step S20, a second vacuum suction process is performed. The second vacuum sucking step is a step in which the valve element 33 is opened (see Fig. 3) at the final stage of the vacuum sucking operation, and the sucking- Process. It is preferable to shorten the exhaust time by increasing the lift amount La and the outer circumferential length of the valve element 33 to a large extent because exhausting as a molecular flow generally requires time.

In step S30, the leaving step (leaving mode) is executed. The releasing step is a step of stopping the cylindrical sliding member 32 for a predetermined period of time in a state in which the first sliding range Lb is directed to the vacuum sliding chamber S. That is, in the release mode, the piston rod 31 moves the first sliding range Lb toward the outside of the vacuum sliding chamber S from the side of the vacuum chamber 40 into the vacuum sliding chamber S. In this state, the vacuum suction passage 23 is provided so that the vacuum suction chamber S is vacuum-sucked only for a predetermined time. As a result, it is possible to disengage the working air adhering to the first sliding range Lb in the cylindrical member 32. This desorption process is executed when a higher degree of vacuum (for example, high vacuum) is required. Further, the time for stopping the first sliding range Lb in the vacuum sliding chamber S is appropriately determined corresponding to the vacuum degree of the required vacuum chamber 40, and the like.

Further, the present step is carried out in such a manner that the cylindrical member 32 is provided with an opening in the vacuum chamber 40 and the outside of the vacuum chamber 40 to the outside of the vacuum sliding chamber S Range Lb) of the lift amount La is increased. In order to shorten the time for stopping the cylindrical member 32, a heater for accelerating the release may be provided inside the piston rod 31. [

In step S40, a conductance operation step is performed. The conductance operating step is a step of controlling the degree of vacuum in the vacuum chamber 40 while flowing an etching gas. In the conductance operation step, the vacuum control is performed on the basis of the control side (conductance operation mode) in which the first sliding range Lb is not exposed to the inside of the vacuum chamber 40. That is, in the conductance operation mode, when the piston rod 31 is reciprocally moved by the driving unit 70, the range of the piston rod 31 toward the inside of the vacuum chamber 40 is the same as that of the vacuum chamber 40, And the vacuum sliding chamber (S). In this case, it is possible to move the second slidable member (not shown) movable from the inside of the vacuum chamber 40 with the sealing member 68 to the outside of the vacuum chamber 40 (the vacuum sliding chamber S or the valve opening operation chamber 36) The range Lc (see Fig. 3) is set to be short.

The conductance operation can also be carried out in such a manner that the lift amount La is reduced to such an extent that the O-ring 35 of the valve element 33 abuts against the valve seat 43 in accordance with necessity. Thereby, the vacuum control without boundary in a wide range from the shutoff to the viscous flow or the molecular flow is realized while preventing the leakage of the working air to the vacuum chamber 40 as the vacuum flow path.

As described above, the above-described embodiment has the following advantages.

(1) The vacuum control valve 10 of the present embodiment has a shutoff function and can realize vacuum control from the initial stage of vacuum suction of the vacuum chamber 40 using plasma to the high vacuum region.

(2) Since the vacuum control valve 10 is a vacuum control valve of a poppet type, it is possible to cope with the property of the etching gas (microstructure) by taking advantage of its characteristics.

(3) The outer surface of the cylindrical member 32 has a smaller amount of gas adsorbed per unit area than the outer surface of the piston rod 31. This makes it difficult for the gas to adhere to the cylindrical member 32, and it is possible to suitably suppress the gas attached to the cylindrical member 32 from being transported to the inside of the vacuum chamber 40.

(4) Since the attaching portion 31c is made of aluminum, which is a metal member, it is possible to suppress the material ratio and the machining cost compared with the case where the sintered body such as the cylindrical member 32 is employed.

(5) Since the linear bearing 85 guides the guide rod 38, it is possible to move the piston rod 31 stably. Therefore, it is not necessary to provide a guide mechanism for the cylindrical member 32 in the sliding portion 60, and it is possible to secure the sealing property in the sliding portion 60. [

(Other Embodiments)

The present invention is not limited to the above embodiment, and may be carried out as follows, for example. Further, the same members as those of the above-described embodiment are denoted by the same reference numerals, and a description thereof will be omitted.

(1) In the first embodiment, the case where the valve element 33 of the linear actuator A is made and used as the vacuum control valve 10 for controlling the degree of vacuum inside the vacuum chamber 40 has been described. However, the linear actuator can be applied to other linear actuators as long as it is used in the vacuum chamber 40 using plasma.

For example, as shown in Fig. 8, as a second embodiment, the arm (actuating part) 80 operable in the vacuum chamber 40 is linearly moved (vertically moved in Fig. 8) by the linear actuator B . The arm 80 operates a work (not shown) such as a substrate, for example, which is etched in the vacuum chamber 40, as shown in Fig. The arm 80 is provided with a pair of arms 80b and 80b made of a turning material (opening degree adjusting material) on the arm body 80a so as to operate the workpiece by both arm portions 80b and 80b.

The linear actuator B according to the second embodiment is provided with a plurality of linear actuators B extending in the direction of movement of the piston rod 31 and extending in the direction of movement of the piston rod 31, A passage 95 is formed. The head cover 81 is not provided with the probe mounting portion 91 described in the first embodiment and one end of the insertion passage 95 is located outside the vacuum chamber 40 (The outside of the main body 71). On the other hand, the other end of the insertion passageway 95 is directed to the arm 80. That is, the insertion passage 95 communicates the outside of the vacuum chamber 40 with the arm 80 while ensuring the sealing property in the vacuum chamber 40.

A control line 96 derived from a driving source (not shown) for driving the arm 80 is inserted into the insertion passageway 95 so that the control line 96 is connected to the arm body 80a . Specifically, in the case of the air pressure type in which the arm 80 is driven by air pressure, the control line 96 may be a pair of pneumatic tubes for supply and exhaust. In the case of the transmission system in which the arm 80 is driven by electric power, the control line 96 may be a wiring for controlling the arm 80 in addition to a power line for supplying electric power. Concretely, there are wirings derived from a position sensor for detecting the positions of the arms 80b and 80b.

In this way, even when the embodiment is embodied as the linear actuator B that linearly moves the arm 80, the transportation of the gas into the vacuum chamber 40 is suppressed and the inside of the vacuum chamber 40 It is possible to keep it with a high degree of vacuum. It is also possible to connect the control line 96 to the arm 80 without lowering the vacuum degree of the vacuum chamber 40 by forming the insertion passage 95 in the linear actuator B.

Furthermore, in the case of only moving the position of the above-mentioned workpiece in the linear direction, it is not necessary to form the arm 80 in the attachment portion 31c of the linear actuator B. That is, as in the case of the linear actuator C shown in Fig. 10, the workpiece may be moved by restricting the workpiece with the attachment portion 31c of the piston rod 31 moving linearly. In this case, since the end portion (the attachment portion 31c, the bolt 33a, etc.) of the operation portion 30 is flushed to the plasma, it is necessary to secure the insulating property.

Thus, the surface oxidation process is performed on the end of the operating portion 30 of the linear actuator (C). Specifically, as the surface oxidation treatment, an alumite treatment is performed. As a result, the end portion of the operation section 30 can be made less susceptible to the influence of the plasma. The linear actuator C is not an attachment portion 31c having a protruding portion in the axial center portion but a flat attaching portion is formed at the end portion of the piston rod 31, May be moved.

(2) In the case of moving linearly to the linear actuator, a gate valve (not shown) can be additionally provided in addition to the valve element 33 and the arm 80 described above. The gate valve may be used as a load lock chamber and a process chamber of a semiconductor manufacturing apparatus using plasma, or may be used as a separation between a transfer chamber and a process chamber. Even in this case, it is possible to linearly move the gate valve by the linear actuator while maintaining the degree of vacuum in the vacuum chamber 40. As a result, it is possible to open and close the gate without lowering the degree of vacuum in the vacuum chamber 40.

(3) In the first embodiment, the linear actuator A has been described by exemplifying a vacuum control valve used in a vacuum chamber 40 for an etching process using plasma. However, the present invention is not limited to this, and it is possible to apply the above-described linear actuator to a vacuum control valve used in a vacuum chamber 40 which generally uses plasma.

(4) In the first embodiment, the linear actuator A generates a driving force with the operating air, but may be configured to be driven by using an electric motor. The above-described configuration can be applied to a linear actuator that linearly moves a wide pop valve element. The control device of the linear actuator can be mounted as a control part (control part) for executing electric power supply to the electric motor and control of the working fluid (for example, control of the control valve) in the valve opening operation chamber 36 . The control unit includes a CPU, a memory, and a computer program.

Furthermore, the working fluid is not limited to the working air, and other types of gas (gas or liquid) such as nitrogen gas may be used.

(5) In the above-described embodiment, the stroke limiting surface 84 of the head cover 81 and the stroke limiting end portion 56 of the operating portion 30 provide the piston rod 31 with the first sliding range (Lift amount La) as when the lift amount Lb is generated. However, for example, the stroke limiting surface 84 and the stroke limiting end portion 56 may be relatively close to each other so that the first sliding range Lb does not occur in the piston rod 31. [ In this case, since the second sliding range Lc facing either the vacuum chamber 40 and the vacuum sliding chamber S or the valve opening chamber 36 is shortened, the second sliding range Lc is set to be It is possible to put it within the range of the vacuum sliding chamber S.

However, the former has an advantage that it is possible to facilitate the vacuum suction of the molecular region, and the latter has the advantage of having the fail-safe property that it is possible to reliably prevent the leakage of the working fluid mechanically.

It is also possible to freely set the limit range of the lift amount La by providing a plurality of kinds of head covers 81 having different positions on the stroke limiting surface 84 and selecting the head cover 81. [ In addition, the position of the stroke limiting surface 84 may be manually or electrically adjustable.

(6) In the above embodiment, as the cylindrical member 32, ceramics in which aluminum oxide is heated and hardened is used. However, as the cylindrical member 32, for example, aluminum nitride, aluminum titanate, boron nitride, zirconia, or the like may be used. However, when aluminum oxide (alumina) is used, it is possible to easily obtain high rigidity and insulation.

(7) In the above-described embodiment, the cylindrical member 32 is configured so as to cover substantially the whole of the moving direction of the piston rod 31. However, the cylindrical member 32 is provided on either side of the inside of the vacuum chamber 40 and the outside of the vacuum chamber 40 (the vacuum sliding chamber S or the valve opening operation chamber 36) in the piston rod 31 (The second sliding range Lc). Therefore, if the cylinder rod 32 covers only the second sliding range Lc of the piston rod 31, the size of the cylindrical member 32 becomes smaller and the material ratio of the cylindrical member 32 becomes smaller .

In the above-described embodiment, the cylindrical piston rod 31 is used as the moving member. However, the moving member may be an elliptical or polygonal columnar member. Also, the covering member is not limited to the cylindrical shape as in the embodiment, but may be formed of an elliptical or polygonal cylindrical member in cross section in accordance with the sectional shape of the moving member.

23 ... Vacuum aspiration flow path, 31 ... The piston rod (moving part), 31a, 31b ... O-rings (elastic sealing parts), 31c ... Attachment, 32 ... Cylindrical member (covered part), 36 ... Valve opening operation chamber (operation chamber), 38 ... Guide rod, 40 ... Vacuum chamber, 49 ... The opening, 51 ... Piston, 60 ... Sliding portion (sliding bag portion), 60b ... Sliding face, 67 ... V packing (second sliding bag member), 68 ... The sealing member (first sliding sealing member), 68a ... Lip, 68e ... Metal spring (taxe), 68f ... Rotobarisu (elastic), 70 ... A driving unit 71, Cylinder tube (cylinder), 75 ... Busan Spring (Busan), 80 ... Arm (operating part), 85 ... Linear bearings (guide part), 95 ... Insertion passage, 96 ... Control line, S ... Vacuum sliding chamber.

Claims (17)

A linear actuator for use in a vacuum chamber in which plasma is generated,
A moving unit capable of reciprocating in a linear direction from the outside to the inside of the vacuum chamber with an opening formed in the vacuum chamber;
A driving unit for reciprocating the moving unit,
A covering portion covering the moving portion,
And a sliding seal portion formed in the opening portion and sealing the space between the inside of the vacuum chamber and the outside of the vacuum chamber while sliding the cover portion,
The covering portion is configured to cover a range of an inside of the vacuum chamber and an outside of the vacuum chamber in the moving portion when the moving portion reciprocates by the driving portion,
The outer surface of the covering portion is configured such that the amount of gas adsorbed per unit area is smaller than the outer surface of the moving portion
And the linear actuator. The method according to claim 1,
Wherein an attaching portion is formed at an end portion of the moving portion toward the inside of the vacuum chamber, the attaching portion having a larger amount of gas adsorbed per unit area than the outer surface of the cover portion. The method according to claim 1,
Wherein the covering portion has a sintered body of insulating property, in which a nonmetallic material having an insulating property is heated and hardened by heat treatment. The method of claim 3,
Wherein the sintered body is composed of ceramics heated and hardened by aluminum oxide. The method according to claim 1,
Wherein the moving unit is made of a metal material. 6. The method of claim 5,
Wherein the moving unit is made of aluminum. 3. The method of claim 2,
Wherein the attaching portion is formed by surface-oxidizing a metal material. 8. The method of claim 7,
Wherein the attaching portion is made of aluminum,
Wherein the surface oxidation treatment is an alumite treatment. The method according to claim 1,
A guide rod connected to the moving unit and extending along the center of the axis of the moving unit;
And a guide portion for guiding the guide rod in a moving direction of the moving portion. 3. The method of claim 2,
And an actuating portion attached to the attaching portion and operating within the vacuum chamber. 11. The method of claim 10,
And a passageway for allowing the control line for controlling the operation of the actuating portion to pass from the outside of the vacuum chamber to the inside of the actuating portion. The method according to claim 1,
The covering portion is provided with a pair of elastic sealing portions which are mutually spaced apart from each other in the moving direction of the moving portion so as to have a predetermined gap with respect to the outer surface of the moving portion,
Wherein the pair of elastic sealing portions elastically abuts the outer surface of the moving portion and seals the predetermined gap. The method according to claim 1,
The slide fastener according to claim 1,
A sliding surface on which said cover portion is slidable,
A first sliding bag member and a second sliding bag member which are spaced apart from each other in the moving direction of the moving portion and which are disposed on the sliding surface and define a vacuum sliding chamber between the sliding surface and the covering portion;
And a vacuum suction passage communicated with the vacuum sliding chamber,
The first sliding sealing member comes into contact with the outer surface of the covering portion to seal between the inside of the vacuum chamber and the vacuum sliding chamber,
Wherein the second sliding sealing member contacts the outer surface of the cover and seals between the vacuum sliding chamber and the outside of the vacuum chamber and the outside of the vacuum sliding chamber,
And the inside of the vacuum sliding chamber is configured to be vacuum-sucked with the vacuum suction passage. 14. The method of claim 13,
Wherein the first sliding bag member comprises:
An elastic body having a bifurcated lip, the split lip contacting the contact surface and the covering portion,
And a biasing member biasing the split lip in a direction in which the split lip is separated from each other. The linear actuator according to claim 13,
And a control unit for controlling the linear actuator,
Wherein the control unit controls the driving unit to move the range of the moving unit toward the inside of the vacuum chamber within the range of the vacuum chamber and the vacuum sliding chamber when the moving unit reciprocates by the driving unit, Mode. 16. The method of claim 15,
Wherein the control unit controls the moving unit such that a range of the moving unit from the vacuum chamber toward the outside of the vacuum sliding chamber is set within the vacuum sliding chamber before the start of the conductance operation mode by the driving unit Wherein the vacuum suction passage is provided in a state in which the vacuum suction chamber is moved and the vacuum suction chamber is evacuated only for a preset time. The method according to claim 1,
The driving unit includes:
A cylinder disposed outside the vacuum chamber and through which the working fluid flows,
A piston which is arranged to define a working chamber inside the cylinder and moves in the cylinder by the pressure of the working fluid supplied into the working chamber;
And a sub-assembly for biasing the piston toward the vacuum chamber,
And the moving unit is connected to the piston.

Images